用高阶对比度研究光束的小尺度自聚焦  

Study of small-scale self-_focusing in laser beams by high-order contrast

作　　者：易煦农[1] 胡巍[1] 罗海陆[1] 朱静[1] 

机构地区：[1]华南师范大学传输光学实验室,广州510631

出　　处：《物理学报》2005年第2期749-754,共6页Acta Physica Sinica

基　　金：国家自然科学基金面上项目 (批准号 :60 2 780 13 ) ;教育部霍英东教育基金会 (批准号 :810 5 8) ;国家高技术研究发展计划专项经费部分资助的课题~~

摘　　要：提出了高阶对比度这一新参数来描述光束的近场均匀性 ,并用之研究高功率激光装置中的小尺度自聚焦现象 .分析了高功率光束小尺度自聚焦发生的过程中填充因子、调制度、对比度及高阶对比度随B积分值的变化 ,指出高阶对比度在光束出现自聚焦成丝前后有更显著的变化 ,所以是描述小尺度自聚焦效应的理想参数 .In this paper, high-order contrast is brought forward for studying small-scale self-focusing phenomenon in high-power solid state laser drivers. Based on the properties of semi-invariant, we obtain the analytic expressions of high-order contrast of near field of beams. Finally, we study the propagation of plane waves with PSD phase noise and obtain the evolution of fill factor, modulation, contrast, third-order contrast and fourth-order contrast with B-integral value. Comparing the results of numerical simulation, we find that third-order contrast and fourth-order contrast are good parameters for characterizing the small-scale self-focusing phenomenon.

关 键 词：对比度 小尺度自聚焦 光束 高功率激光 B积分 近场 高阶 成丝 理想 填充因子 

分 类 号：O437.5[机械工程—光学工程]